Carburetor



D. COLLINS Aug. 2, 1932.

CARBURETOR Filed April 22, 1950 2 Sheets-Sheet 1 v Ihwentor Java/J5 00Lu/rs (Jttorneg Au 2, 1932. D, COLLINS 1,869,467

CARBURETOR Filed April 22. 1930 ZSheets-Sheet 2 27 fie- 6.

'Jnvcntor JOUGLflS OOLLl/YS attorney Patented Aug. 2, 1932 I STATESPATENT OFFICE DOUGLAS COLLINS, OF SALISBURY, NORTH CAROLINA CARIBURETORApplication filed April 22, 1930. Serial No. 446,367.

My present invention relates to improve- My invention consists incertain novel com-. ments in carburetors for'use with internal binationsand arrangements of parts as will" combustion engines employed asmotorsfor hereinafter be more fully set forth and automotivevehicles,aircraft, and watercraft, claimed. As here illustrated, theinvention and the invention applies particularly to the is embodied asan attachment at the air in- 65 air valve or choke by means of which thetake portion of the carburetor, and the caradmission of air for dilutingthe fuel mixburetor illustrated is of conventional type. ture isautomatically controlled and gov- It will be understood that theautomatically erned. In carrying out my invention I utioperating valvemechanism may form an inli'ze motiv fluid a r ur fr both th tegralelement of a carburetor to which the 60 exhaust manifold, and suctionfrom the ininvent-ion is adaptable. In the accompanytake manifold, ofthe engine or motor for ing drawings I have illustrated one completeautomatically controlling the position of the example of the physicalembodiment of my chok r air valve, to govern and regulate inventionwherein the parts are combined and the admission of air to thecarburetor for arranged according to one mode I have sucdelivery to thefuel mixture. The automatessfully operated for carrying out theprinically operating air control device or choke, pl s Of my invention.also depends in some instances and under Figure 1 is a View of a typicalmotor some conditions, upon the position of the equipped with the deviceof my invention.

standard throttle valve that controls and gov- 1 Figure '2 is anenlarged side view of Y a W erns the admission of the fuel mixture,after standard type of carburetor with which my carburetion. to thecylinders of the motor. device is combined.

The choke or air valve is of the gravity Figure 3 is a detail view,partly in secoperated type, and I utilize a spring or other tion,showing the connection to the exhaust means, for holding the valve inclosed posimanifold for obtaining motive fluid pressure. 75 tion, in theabsence of motive fluid pressure Figure 4.-is a view ,in elevation (asseen capable of opening the air valve. from the front of the motor)ofth'e automati- As is well known, when the motor of an Cally op ratingV lve C fO vice. automotive vehicle .is already heated from Figure 5 isa view in elevation at the inprevious operations of the motor, orduringner side of the air valve mechanism or choke. 30

hot weather" conditions or other natural Figure 6 is a verticalsectional view of causes, a rich fuel mixture is not required for thedevice. starting the firing of the cylinders. Under In Order that thegeneral arrangement and such conditions the air valve is automaticallyrelation of parts may readily be understood, opened for the admission ofair to dilute th I have shown in Figure 1 a conventional mo- 85 fuelmixture. When the engine or motor is tor or internal combustion engine 1with the 1d d especially h n the motor is exusual fan 2 at the front andthe fly wheel 3 posed to cold weather conditions. a rich fuel at therear. The intake manifold for feedmixture is required to fire thecylinders, and ing the fuel'mixture into the engine cylinders after theengine is running smoothly the is designated as 4, while the exhaustmanirich mixture may be diluted. At starting, fold and exhaust pipe aredesignated by when the motor is coldand an undiluted mixthe numeral 5,and connections are made to ture is required. the air valve is preventedthese manifolds that areinstrumental in the from opening and dilutingthe fuel charge beautomatic operation of the air valve of the cause ofconditions existing in the valve mech- Carburetor. anism due to the openor partly open position A well known type, of carburetor is illusofthethrottle valve, which latter valve is of trated as attached .by-i sfl ng6 0 he in k course manipulated to permit flow of fuel manifold, andthe carburetor throat or fuel mixture from the carburetor to the intakepipe 7. fr m h Q III I" has h in the 10 manifold. usual throttle valve8, operated by a lever 9 v that is pivoted at 10 on the fuel pipe, andmanually, or pedal, operated, (or otherwise controlled) by suitablemechanical connections including the pivot rod 11.

The float chamber 12 of the carburetor receives liquid fuel from asuitable source of supply, and the fuel therefrom passes through thebody13 of the carburetor to the fuel pipe 7. p

Air for the fuel mixture is admitted to the carburetor through the airintake pipe 14, and my automatically operating valve control device orchoke is mounted on the air intake The choke device, as an attachment,includes an air chamber 15, and the casing of the chamber is fashionedwth an attaching collar 16 which may be cylindrical to fit over thecylindrical air intake pipe, and the device is fastened on the airintake pipe by means of a set bolt 17 orother suitable means.

The air valve or choke valve 18 is a flat, light, metal plateadapted toclose the-open end or air inlet port of the chamber 15, and this valveis secured on a pivot pin 19 that is journaled in a slot 20 in thecasing, above the chamber 15. The two projecting ends of the pivot pinare supported or journaled in two oppositely arranged trunnion-bolts 21,and these bolts are threaded and adjustable in the brackets 2:2 and 23fashioned integral with or fixed to the outer, opposite sides of thevalve-casing. The bolts are adjusted to minimize the friction at thebearing ends of the pivot pin to insure the required freedom of pivotalmovement of the valve and p1n.-

A'spring 24 is coiled about the pivot pin with its inner end anchored tothe pin and its outer end anchored to a clip 25 that is fixed to thecasing in proper position for the purfor the motor.

Above the air passage or chamber 15 is fashioned a pressure chamber 26in which is located a valve lever or pressure plate 27 rigid with thepivot pin 19 and the valve 18, and fixed in a plane parallel with thevalve. It will be seen from the dotted lines in Figures 5 and 6 that thevalve and pressure plate-swing with the pivot pin as a center, underinfluence of motive fluid pressure imposed against the outer face of thepressure plate. This pressure may be imposed directly by exhaust gasesfrom the exhaust manifold, against the left face of the plate in Figure6, or when suction is present at the right side of the plate,atmospheric or other pressure is caused to be applied at the left sideof the plate, to swing the latter withothe valve.

i A suction tube 28 passes upwardly through the air chamber 15 and hasan open upper end or port 29 in the pressure chamber 26. This suctiontube has a nipple, or other suitable joint, coupled to a suction pipe 30that is attached to the intake manifold of the motor, and the pipecommunicates at all times with the interior of the intake manifold. Whenthe pistons create suction in the cylinders, the suction, under someconditions, is sufficient to cause the pressure plate to swing, and openthe valve 18, as indicated by dotted lines.

To introduce motive fluid pressure. from the exhaust manifold to thepressure chamber 26, I utilize a flexiblepipe 3,1 that is attached atone end to the boss 32 located near the top of the casing, and openinginto the pressure chamber. The exhaust manifold is provided with a holeor port 33 drilled therein,

and a clamp plate, or curved shoe 34 conforming to the shape of theexhaust pipe or manifold, is secured about the ported part of the pipeby means of U-bolts 35, or in other suitable manner. An asbestos packingor gasket 36 is interposed between the clamp plate and the exhaust pipeto prevent escape of gases, andtheplate is fashioned with a boss 37 inwhich a nipple 38, on the flexible pipe, is threaded. V

It will be apparent that the flow of exhaust gas through the flexiblepipe, against the outer face of the pressure plate 27, will tend toswing the plate and the valve on the pivot pin, to open the valve foradmission of air to the carburetor.

Assuming the engine to be started by the operation of the usual startingmotor, or otherwise, with the throttle 8 in its minimum open positionand before the exhaust gases are produced by firing in, the cylinders,the suction created by the reciprocating pistons extends through theintake manifold to the carburetor, and to the pressure chamber. Thesuction through the suction pipe 30 from the pressure chamber, however,is greater than the suction through the throat of the carburetor, or thefeed pipe 7, because of the fact that the throttle valve is onlypartially opened, i. e. open to its minimum area.

Therefor'ethe suction through pipe 30 pergine is already heated fromprevious opera-- tions, or when the engine is warm due to weatherconditions, this described operation of the valve takes place.

If the motor is cold, it is necessary or desirable, to advance or openthe throttle valve 8, and thereby admit a larger vol ume of fuel mixtureto the cylinders for starting the engine, and this fuel mixture shouldbe richer than the quality of the fuel mixture employed when the engineis hot. Thus, when the motor is cold, the air valve or choke is requiredto remain closed against admission of air that would dilute the requiredrich fuel mixture. Under such conditions the suction pipe 30 and thethroat of carburetor, or pipe 7 contain a suction from the engine thatis more nearly equalized, due to the fact that the throttle valve isopen wider than is required when starting the engine while the latter ishot. The-spring 24 therefore holds the choke or air valve closed andprevents dilution of the rich fuel mixture.

After the engine is started and the cylinders are firing smoothly, thespeed of the engine creates such a degree of suction as to open the airvalve or choke, especially if the throttle has been returned to itsminimum open position. With the engine running and the cylinders firing,the pressure of the exhaust gases in the pressure chamber is suflicientto swing open the choke or air valve to admit air to the fuel mixture,and the quality of the fuel mixture is thus properly maintained forefficient running of the engine with a minimum consumption of fuel.

Frequently, after the motor is started, it begins to spit indicatingthat an additional choking is required. This condition is remedied bydepressing the throttle pedal or advancing the hand lever of thethrottle, to open the throttle 8 (a natural performance under thecircumstances) and consequentlv the suction through the carburetor andthrough the suction pipe and chamber 26 is equalized. Now if the engineexhaust weak (due to the fact that the engine is starving for fuel andneeds choking) the exhaust will be insuflicient to hold the choke valveagainst the pressure of the spring. and the choke valve will close. thuschoking the engine. The cycle of starting is then repeated. so that thechoke. when the motor exhaust is weak. will close whenthe accelerator'or foot throttle is depressed,- and open when the pedal is released. If.however. the motor. is firing naturally and does not require choking,the exhaust gases will at all times hold the valve. in open position.

It will thus be seen that I have devised a choke which is operated bythe pressure of exhaust gases of the engine, assisted and controlled bythe intake suction of the engine manifold, and the choke is controlledin itsoperatio'n by manipulation of the throttle valve of the engine.

The consumption of liquid fuel is thus varied, and the quality of thefuel mixture is controlled and regulated by the automatic operation ofthe choke valve, due to the motive fluid pressure as described.

Having thus fully described my invention, what I claim asnew and desireto secure by Letters Patent is 1. A valve control mechanism comprising aported air chamber and choke valve therefor, a pressure chamber andapressure operated lever therein rigid with the valve, means forintroducing fluid pressure to the pressure chamber and resilient meansfor holding the valve in closed position.

2. The combination of a valve casing having an air chamber, a pivotedvalve for controlling passage of air through said chamber, said casinghaving a. pressure chamber and means for introducing motive fluid tosaid pressure chamber, a pressure plate in said chamber and rigid withthe valve, and a spring for holding the valve in closed position.

. 3. The combination of a valve casing having an air chamber, a pivotedvalve for controlling passage of air through said chamber, said casinghaving a pressure chamber and means for introducing fluid pressure tosaid chamber, a pressure plate in the pressure chamber and rigid withthe valve, and a suction pipe having a port on said pressure chamber. v

4. In a carburetor for internal combustion engines, the combination of athrottle valve for'the intake manifold, av choke valve for thecarburetor, a pressure chamber adjacent the choke valve, a suction pipebetween the pressure chamber and the manifold, a fluid pressure actuatedelement rigid with the choke valve and located in the pressure chamber,and means for introducing exhaust gases to the pressure chamber. I

5. In an air valve mechanism, the combination with a casing having anair passage 'and a choke valve for controlling admission of air throughsaid passage, sald casing having a pressure chamber, a valve-actuatingelement in the pressure chamber, a suction pipe having a port in thepressure chamber at one side of said element, and a motive fluidpressure pipe having a port to the chamber at theo'ther side of theelement.

6. In a choke mechanism, the combination with a casing having an airpassage and a pivoted choke valve, said casing having a pressure chamberand a valve lever-plate in said chamber, a suction pipe having a port inthe pressure chamber at one side of the lever-plate, and an exhaust gaspipe having a port in the pressure chamber at the opposite side of thelever-plate.

In testimony whereof I aflix my signature.

IQOUGLAS COLLINS.

